1. Field of the Invention
This invention relates to measurement devices for providing a reference point and, in particular, relates to devices used to assist in the installation of fire sprinkler heads.
2. Related Art
The installation of fire sprinkler systems is an important part of building construction. Often, fire sprinkler systems are installed in conjunction with dropped ceilings, which may be secondary ceilings hung below the main structural ceiling. Dropped ceilings may be used to conceal piping, wiring, ductwork, etc. in the plenum space above the dropped ceiling. Dropped ceilings may be constructed of a metal tile grid with a panel (or tile) positioned within the individual cells of the grid. The panels may be constructed from mineral fibers or other suitable materials. Often panels have 2′×2′ (two foot-by-two foot) square dimension or a 2′×4′ (two foot-by-four foot) rectangular dimension.
Installing a fire sprinkler system in a building having dropped ceilings may involve positioning a fire sprinkler head in one of the tile grid panels. In buildings having existing water pipes, the fire sprinkler head may use the existing water pipes as a water source. Further, for aesthetics and reducing potential water damage to adjacent light fixtures and other equipment installed the ceiling, it may be preferred that a fire sprinkler head be positioned in the center of the panel. In the case of 2′×2′ panels, the center of the panel is approximately 1′ (one foot) from each edge of the tile grid cell. Alternatively, in the case of 2′×4′ rectangular panels, the center is approximately 1′ (one foot) and 2′ (two feet) from the respective side edges of the tile grid cell.
However, the distance from the center of the panel and tile grid cell to the nearest water source may vary from building to building. Consequently, the amount of pipe needed to connect the fire sprinkler head positioned at the center of the tile grid cell to the water source may also vary. Those installing the fire sprinkler system may have difficulty in determining the distance from the nearest water source to the center of tile grid cell having the fire sprinkler head. Known techniques may, for example, use a plumb-bob to identify the center of the tile grid cell when measuring from the center of the panel to the nearest water source. However, use of a plumb-bob may be time consuming and cumbersome. Thus, there exists a need for an improved device and method for determining the center of a tile grid cell when installing a fire sprinkler head.